If a person loses a finger, a finger segment, or a fingertip, the result is impaired performance of the hand. Having an amputated finger inhibits an amputee from performing some of the most basic tasks. For example, with a lost finger or fingertip, the task of typing on a computer keyboard or dialing on a telephone becomes significantly more difficult. These types of tasks require precise actions that only fingers are able to offer.
Not only do they allow for the performance of precise physical actions, fingers also provide an increased ability to grip or handle items. While holding an item in the hand, the weight of the item is dispersed through all of a user's fingers. By varying the force used by each finger on the holder's hand, the holder is able to manipulate the item in a myriad of ways. However, if the holder is missing all or even part of a single digit, or if a digit is present but nonfunctioning, this freedom of manipulation and the number of degrees through which the holder can manipulate the item is drastically decreased.
Current prosthetic finger solutions demonstrate several drawbacks. First, a primary category of prosthetic fingers offers only cosmetic restoration. These prosthetics are designed to be worn passively and offer a realistic look. They provide little to no functionality and do not enable the owner to restore functionality to his or her hand. Other prosthetics offer the user some level of restored functionality, but are complex in design and electrically powered. These prosthetics, while perhaps better than going without, are impractical in that they require an external power source and can be both bulky and unwieldy for the user to manage. Still other prosthetic fingers are body-powered but lack the design flexibility necessary to accommodate any length of residual finger (e.g., all or partially amputated and varying degrees of amputation) while providing maximum dexterity, grip strength, and finger articulation.